Introduction

• What is an LVM?
• Logical Volume Manger
• Veritas, Solstice, AIX
• Allows greater flexibility in defining volumes and filesystems
• Ability to span disks
• Resize filesystems without backup
• Linux/Logical Volume Manager
• Hierarchy
• Physical Volumes
• Disks
• Partitions
• "Disk File"
• Logical Volumes
• Volume Groups
• Filesystems
• Creating and Administering an LVM volume
• Create Physical Volumes
• Create a Volume Group from the physical volumes
• Craete a Logical Volume within the Volume Group
• Create a Filesystem withing the Logical Volume
• Growing an LVM-based filesystem
• Unmount the Filesystem
• Extend the Volume Group if needed
• Added Extents to the Logical Volume
• Fsck the Filesytem
• Remount

Demonstration

Start by looking at our existing disks

	cat /proc/scsi/
	dmesg |grep sd
	

Next, partition the new disks using fdisk

	fdisk /dev/sdb
	

p to Print the existing table (should be blank)
n to create a new partition
t to change partition system ID to 8e (Linux LVM)
w to write new table to disk

Repeat for /dev/sdc
Create the physical volumes

	pvcreate /dev/sdb1
	pvcreate /dev/sdc1
	

NOTE: You can create multiple PVs on a single disk, but it is not recommended. Show existing Physical Volumes

	pvscan
	

Show Volume Groups

	vgscan (should return nothing)
	

Create a Volume Group from the Physical Volumes

	vgcreate opt_vg /dev/sdb1 /dev/sdc1
	

NOTE: You can specify PE size in vgcreate. Default is 4M. You'd use larger PE sizes for LVs greater than 256G. 65K PEs per LV.
Show Volume Groups

	vgscan (now shows the VG we created)
	

Display information about the VG

	vgdisplay 
	

Create a Logical Volume within the VG

	lvcreate -l num_of_extents -n opt_lv opt_vg
	lvcreate -L 100M -n opt_lv opt_vg
	lvcreate -L 100M -n opt_lv -i num_stripes opt_vg
	lvcreate -L 100M -n opt_lv opt_vg [PhysicalVolumePath]
	

Display information about the LV

	lvdisplay
	lvdisplay -m (Show maps. Compare striped vs un-striped)
	

Create a mount point

	mkdir /opt/foo1
	mkdir /opt/striped
	

Create a filesystem

	mkfs.ext3 /dev/opt_vg/opt_lv
	mkfs.ext3 /dev/opt_vg/striped_lv
	

Mount the filesystems

	mount /dev/opt_vg/opt_lv
	df -h 
	

Growing a Filesystem

Grow an EXT2/3 filesystem (with unmount)
Unmount the FS

	umount /mnt/lvm_filesystem
	

Extend the LV

	lvresize -l +50 /dev/opt_vg/opt_lv
	lvresize -L +200M /dev/opt_vg/opt_lv
	

fsck the filesystem

	e2fsck -f /dev/opt_vg/opt_lv
	

Resize the filesystem

	resize2fs /dev/opt_vg/opt_lv
	

Remount the filesystem

	mount -t ext3 /dev/opt_vg/opt_lv /mnt/lvm_filesystem
	

Grow an EXT2/3 filesystem (without unmount)
Extend the LV

	lvresize -l +50 /dev/opt_vg/opt_lv
	lvresize -L +200M /dev/opt_vg/opt_lv
	

Grow the filesystem

	ext2online /mnt/lvm_filesystem (using mount path)
	ext2online /dev/opt_vg/opt_lv (using device)
	

Grow a ReiserFS filesystem
Create a ReiserFS on /dev/opt_vg/striped_lv

	mkreiserfs /dev/opt_vg/striped_lv
	

Mount the FS

	df -h
	lvresize -L +50M /dev/opt_vg/striped_lv
	resize_reiserfs -f /dev/opt_vg/striped_lv
	df -h
	

Add a Physical Volume to a VG

	vgextend vgname /path/to/PV